While waiting for your reply I tried to do a System Restore and received the following error message:
System Restore did not complete successfully. Your computer's system files and settings were not changed.
System Restore failed to replace the file (C:\Windows) with its original copy from the restore point.
An unspecified error occurred during System Restore. (0x80071a90)
I have received this error before as well as one stating that my Anti-Virus might be causing it. However, my firewall was not on and the Restore was operating in a "clean boot" environment with no "start-up" items running and only basic services running (which include the Shadow Copy Service). I also get the same results while running in normal mode (with all start-up items running).
Have you every seen this before?